This paper reviews the taxonomical literature of the gracilarioid algae from Tanzania, and provides information about their ecology and distribution based on an intensive regime of local collection. Its aim was to provide names, even if on a preliminary basis, for local gracilarioid taxa. Our revision shows that species misidentification is widespread and that some species are in need of further critical taxonomic study. Nine species of Gracilaria are reported in the region, including one unidentified Gracilaria or Gracilariopsis.